Process for producing a high-permeability alloy for magnetic recording-reproducing heads

ABSTRACT

A magnetic recording and reproducing heads having a high permeability and high hardness, consisting of 60.2 to 85.0 Wt.% of nickel, 6.0 to 30.0 Wt.% of iron and 3.1 to 23.0 Wt.% of tantalum as the main ingredient, and a total amount of 0.01 to 10.0 Wt.% of at least one element selected from the group consisting of 0 to 7.0 Wt.% of molybdenum, 0 to 5.0 Wt.% of chromium, 0 to 10.0 Wt.% of tungsten, 0 to 7.0 Wt.% of vanadium, 0 to 3.1 Wt.% of niobium, 0 to 10.0 Wt.% of manganese, 0 to 7.0 Wt.% of germanium, 0 to 5.0 Wt.% of titanium, 0 to 5.0 Wt.% of zirconium, 0 to 5.0 Wt.% of aluminum, 0 to 5.0 Wt.% of silicon, 0 to 5.0 Wt.% of tin, 0 to 5.0 Wt.% of antimony, 0 to 10.0 Wt.% of cobalt and 0 to 10.0 Wt.% of copper as the subingredient, and an inevitable amount of impurities, characterized in that the alloy has the degree of order of 0.1 to 0.6, the Vickers hardness of more than 150, the initial permeability of more than 3,000 and maximum permeability of more than 5,000, and a method of manufacturing a magnetic recording and reproducing head having a high permeability, by heating said alloy articles at a temperature above 800*C but lower than the melting point in a non-oxidizing atmosphere or in vacuo for at least more than 1 minute but not longer than 100 hours depending upon the composition, and cooling from a temperature of more than orderdisorder transformation point to a room temperature at a suitable speed depending upon the composition so as to provide the degree of order of 0.1 to 0.6 and the Vickers hardness of more than 150.

States Masumoto et al.

atent [191 Mar. 18, 1975 1 PROCESS FOR PRODUCING A HIGH-PERMEABILITY ALLOY FOR MAGNETIC RECORDING-REPRODUCING HEADS [75] lnventors: l-Iakaru Masumoto, Sendai City;

Yuetsu Murakami, lzumi-Machi; Masakatsu Hinai, Natori City, all of Japan [73] Assignee: The Foundation: The Research Institute of Electric and Magnetic Alloys, Sendai City, Japan [22] Filed: July 20, 1973 [211 Appl. No.: 381,134

Related U.S. Application Data [62] Division of Ser. No. 290,424, Sept. 19, 1972, Pat.

[30] Foreign Application Priority Data Oct. 13, 1971 Japan 46-80207 [52] U.S. C1 ..148/121,75/170,148/120, 148/3155 [51] Int. Cl. H0lf U00 1581 Field of Search 148/121, 120, 122, 31.55, 148/3157; 75/170 [56] References Cited UNITED STATES PATENTS 1,873,155 8/1932 Scharnow 148/3155 2,046,995 7/1936 Austin 75/170 2,921,850 1/1960 lnouye et al. 75/170 3,390,443 7/1968 Gould et al. 148/3157 FOREIGN PATENTS OR APPLICATIONS 1,086,674 10/1967 Great Britain 148/120 Primary ExaminerWalter R. Satterfield Attorney, Agent, or Firm-Sughrue, Rothwell, Mion, Zinn & Macpeak [57] ABSTRACT A magnetic recording and reproducing heads having a high permeability and high hardness, consisting of 60.2 to 85.0 Wt.% of nickel, 6.0 to 30.0 Wt.% of iron and 3.1 to 23.0 Wt.% of tantalum as the main ingredient, and a total amount of 0.01 to 10.0 Wt.7( of at least one element selected from the group consisting of 0 to 7.0 Wt.% of molybdenum, 0 to 5.0 Wt.% of chromium, 0 to 10.0 Wt.% of tungsten, 0 to 7.0 WtT/z of vanadium, 0 to 3.1 Wt.% of niobium, 0 to 10.0 Wt.% of manganese, 0 to 7.0 Wt.% of germanium, 0 to 5.0 Wt.% of titanium, 0 to 5.0 Wt.7r of zirconium. 0 to 5.0 Wt.% of aluminum, 0 to 50 Wt.% of silicon, 0 to 5.0 Wt.% of tin, 0 to 5.0 Wt.% of antimony, 0 to 10.0 Wt.% of cobalt and O to 10.0 Wt.% of copper as the subingredient, and an inevitable amount of impurities, characterized in that the alloy has the degree of order of 0.1 to 0.6, the Vickers hardness of more than 150, the initial permeability of more than 3,000 and maximum permeability of more than 5,000, and a method of manufacturing a magnetic recording and reproducing head having a high permeability, by heating said alloy articles at a temperature above 800C but lower than the melting point in a non-oxidizing atmosphere or in vacuo for at least more than 1 minute but not longer than 100 hours depending upon the composition, and cooling from a temperature of more than order-disorder transformation point to a room temperature at a suitable speed depending upon the composition so as to provide the degree of order of 0.1 to 0.6 and the Vickers hardness of more than 150.

4 Claims, 10 Drawing Figures @RYEIHEU 8W5 3,871.92?

SHEETlQfE} /o) INITIAL PERMEABILITY 0F Ni-FeTu-Mo ALLOY (Mo BEING ABOUT 21%) AXIUMPRMEABILITY 0F Ni-Fe-To-Mo ALLOY (Mo BEING ABOUT 2.1%)

SHEET 2 [IF 5 HIE HAR 1 8 197 (Cr BEING ABOUT 2.2%)

HM. 3E MAXIMUM PERMEABILITY 0F Ni-Fe-Tu-Cr ALLOY j I' 'I'EHTEUIINI I 8|9'r5 3 71,927

SHEET 3 o 5 INITIAL PERMEABILITY OF Ni-Fe-T0-W ALLOY (W BEING ABOUTEE I PERMEABILITY 0F Ni-Fe-Tu-W ALLOY (W BEING ABOUT 3.2%)

BBL U, m

BBTBBIEB 8% (v BEING ABOUT 3.0%)

(v BEING ABOUT 30%) |mL PEMABILITY 0F Ni-Fe-To -V ALLOY SHEET 5 5 PATENTEUHARI 8l9?5 INITIAL 'PERMEABIUTY 0F Ni-FeTu-GeALLOY (Ge BEING ABOUT 3.I%)

MAXIMUM PERMEABILITY 0F Ni-Fe-Tu-Ge ALLOY (Ge BEING ABOUT 3.1%)

PROCESS FOR PRODUCING A HlGH-PERMEABILITY ALLOY FOR MAGNETIC RECORDlNG-REPRODUCING HEADS This is a division of application Ser. No. 290,424, filed Sept. 19, 1972 now US. Pat. No. 3,794,530.

This invention relates to a high-permeability alloy for magnetic recording-reproducing heads, which alloy consists of 60.2 to 85.0 Wt.% of nickel, 6.0 to 30.0 Wt.% ofiron, 3.1 to 23,0 Wt.% of tantalum as the main ingredient, and further consists of the total amount of 0.01-10.0 Wt.% selected from the group consisting of to 7.0 Wt.% of molybdenum, 0 to 5.0 Wt.% of chromium, 0 to 10.0 Wt.% of tungsten, O to 7.0 Wt.% of va-' nadium, 0 to 3.1 Wt.% of niobium, 0 to 10.0 Wt.% of manganese, 0 to 7.0 Wt.% of germanium, 0 to 5.0 Wt.% of titanium, 0 to 5.0 Wt.% of zirconium, 0 to 5.0 Wt.% of aluminum, 0 to 5.0 Wt.% of silicon, 0 to 5.0 Wt.% of tin, 0 to 50 Wt.% of antimony, O to 10.0 Wt.% of cobalt, and 0 to 10.0 Wt.% of copper as the subingrediant, and an inevitable amount ofimpurities, and to provide a method of making the alloy with such composition and having a high permeability. The object of the present invention is to provide an alloy having a high permeability, a high hardness, a high specific resistivity and further a high forgeability and high workability through simple heat treatment, so as to provide a magnetic alloy for the use of magnetic recordingreproducing heads. having excellent magnetic property.

Permalloy (Nickel-iron alloy) is widely used at the present in magnetic recording-reproducing heads of audio tape recorder, because it has a high permeability and high workability. The conventional Permalloy, however, has a shortcoming in that its Vickers hardness Hv is in the order of about 130 and comparatively low, so that its abrasion resistivity is rather poor. Accordingly, there has been a pressing need for improving the hardness and abrasion resistivity of alloy materials for magnetic recordingreproducing heads.

To achieve an object of the invention, the applicants have carried out a series of tests on alloys, which have a permeability higher than that of binary Permalloy and high hardness and high electric resistivity, while maintaining a high forgeability and high workability. As a result, the applicants have found out that, with the addition of 3.1 to 23.0 Wt.% of tantalum into nickel-iron alloys, magnetic and mechanical properties of the alloy can noticeably be improved.

The applicants have further found out that, with the addition of the total amount of less than 10.0 Wt.% of one or more than one of Mo, Cr, W, V, Nb, Mn, Ge, Ti, Zr, Al, Si, Sn, Sb, Co and Cu as the subingredient into nickel-iron-tantalum alloys, and can provide an alloy having high permeability, high hardness and high specific resistivity, along with high forgeability and high workability According to the present invention, there is provided an alloy consisting of 60.2 to 85.0 Wt.% of nickel, 6.0 to 30.0 Wt.% ofiron, and 3.1 to 23.0 Wt.% of tantalum as the main ingredient, and further consisting of the total amount of 0.01 to 10.0 Wt.% selected from the group consisting of 0 to 7.0 Wt.% of molybdenum, 0 to 5.0 Wt.% of chromium, 0 to 10.0 Wt.% of tungsten, 0 to 7.0 Wt.% of vanadium, 0 to 3.1 Wt.% of niobium, 0 to 10.0 Wt.% of manganese, O to 7.0 Wt.% of germanium, 0 to 5.0 Wt.% of titanium, 0 to 5.0 Wt.% of zirconium, 0 to 5.0 Wt.% of aluminum, 0 to 5.0 Wt.% of silicon, 0 to 5.0 Wt.% of tin, 0 to 5.0 Wt.% of antimony, 0 to 10.0 Wt.% of cobalt, and O to 10.0 Wt.% ofcopper as the subingredient, and an inevitable amount of impurities, which alloy has a high initial permeability, e.g., higher than 3,000, a high maximum permrability, e.g., higher than 5,000, a Vickers hardness greater than 150, a high specific resistivity, high forgeability and high workability. The alloy of the invention can easily be heat treated and formed into the shape of magnetic recording-reproducing heads.

According to the present invention, it is more preferable to provide an alloy consisting of 70.0 to 80.0 Wt.% of. nickel, 8.0 to 20.0 Wt.% of iron and 6.0 to 17.0 Wt.% of tantalum as the main ingredient, and further consisting of the total amount of 0.01 to 10.0 Wt.% selected from the group consisting of 0 to 4.0 Wt.% of molybdenum, 0 to 3.0 Wt.% of chromium, O to 5.0 Wt.% of tungsten, 0 to 4.0 Wt.% of vanadium, 0 to 3.0 Wt.% of niobium, 0 to 5.0 Wt.% of manganese, 0 to 5.0 Wt.% of germanium, 0 to 3.0 Wt.% of titanium, 0 to 3.0 Wt.% of zirconium, 0 to 3.0 Wt.% of aluminum, 0 to 3.0 Wt.% of silicon, 0 to 3.0 Wt.% of tin, 0 to 3.0 Wt.% of antimony, 0 to 5.0 Wt.% of cobalt, and 0 to 5.0 Wt.% of copper as the subingredient, and a small amount of impurities.

It is possible to obtain the alloy having the high permeability and the high hardness by a process comprising steps of heating the alloy in vacuo or in a nonoxidizing atmosphere, for the purpose of removal of work strain, thorough solution treatment and homogenization, at 800C or higher, preferably 1,100C and lower than the melting point, for at least more than 1 minute, but not longer than about hours depending on the alloy composition; cooling the alloy to a temperature above its order-disorder transformation point, e.g., about 600C, so as to keep the alloy at the lastmentioned temperature for a short while until uniform temperature is established throughout the alloy; and cooling the alloy from the temperature above the order-disorder transformation point to room temperature at a rate faster than 1C/hour but slower than 100C/second depending on the alloy composition, 'or further heating the alloy at a temperature below the order-disorder transformation point for at least 1 minute but not longer than 100 hours depending on the alloy composition and cooling it to room temperature.

The reason why the heating temperature for the purpose of the aforesaid removal of work strain and thorough solution treatment is defined above 800C, preferably above 1,100C, is that the temperature above the recrystallizing temperature (about 600C) can improve the magnetic properties of the alloy, but the temperature above 800C, preferably above 1,100C, can result in an outstanding improvement of the magnetic properties of the alloy.

The manner in which the alloy is cooled from the temperature of solution treatment to a temperature above its order-disorder transformation point (about 600C) does not affect its magnetic properties so seriously, regardless of whether it is cooled slowly or quenched. The cooling speed when the alloy temperature becomes under its orderdisorder transformation point has profound effects on the magnetic properties of the alloy, and hence, it is necessary-to cool the alloy from its order-disorder transformation point at a rate faster than 1C/hour but slower than 100C/second depending on the alloy composition to a room temperature. Such rangeof the cooling speed is selected in order to cause the degree of order of the alloy to fall in a range of about 0.1 to 0.6, and the alloy having excellent magnetic properties can be obtained. If its degree of order is in a'range of 0.2 to 0.5, the magnetic properties are further improved. If the alloy is comparatively quenched at about 100C/second, its degree of order becomes comparatively small, e.g., at about 0.1, so that the magnetic properties of the alloy is deteriorated. If the alloy having such small degree of order is reheated at a temperature lower than the orderdisorder transformation point, e.g., 200 to 600C, the

degree of order proceeds 0.1 to 0.6 and the magnetic properties are improved.

On the other hand, excessively slow cooling, slower than 1C/hour, tends to make the degree of order too large in excess of 0.6, so that the magnetic properties are lowered.

The inventors have found that the magnetic properties of the alloy of the invention can be maximized when the degree of order of the alloy falls in a range of 0.1 to 0.6, preferably 0.2 to 0.5. The aforesaid cooling from a temperature above the order-disorder transformation point of the alloy at a rate faster than lC/hour at slower than 100C/second will result in the desired degree of order in'the range of 0.1 to 0.6. The magnetic properties of the alloy thus treated, especially when it In cooling the alloy having the aforesaid composition,

according to the present invention, from a temperature above its order-disorder transformation point of about 600C to room temperature, the proper cooling speed for maximizing its high permeability somewhat varies depending on its composition, but the cooling speed to beused in the present invention is usually so slow that cooling in a'furnace is preferred.

For instance, after shaping magnetic recordingreproducing heads, such heads are usually heat treated for eliminating internal stress caused in the heads by the shaping process. To retain their proper shape and to avoid the oxidation of'their surface, slow'cooling in vacuo or in a non-oxidizing atmosphere is preferable. The alloy according to the present invention is particularly suitable for such post-shaping heat treatment.

A metliod for making an alloy according to the invention will now be described step by step.

In order to make the alloy of the invention, a suitable amount of a starting material consisting of 60.2 to 85.0 Wt.% of nickel, 6.0 to 30.0 Wt.% of iron and 3.1 to 23.0 Wt.% of'tantalum is melted bya melting furnace in air, preferably in vacuo or in a non-oxidizing atmosphere; a small amount (less than 1 Wt.%) of a deoxidizer and desulfurizer, e.g., manganese, silicon, aluminum, titanium, boron, calcium alloy, magnesium alloy, and the like, is added in the melt for removing impurities as far as possible; and an estimation of the total of less than 10.0 Wt.% selected from the group consisting of 0 to 7.0-Wt.% of molybdenum, 0 to 5.0 Wt.% of

, 4- chromium, 0 to 10.0 Wt.% of tungsten, 0 to Wt.% of vanadium, 0 to 3.1 Wt.% of niobium, 0 to 10.0 Wt.% of manganese, 0 to 7.0 Wt.% of germanium, 0 to 5.0 Wt.% of titanium, 0 to 5.0 Wt.% of zirconium, 0 to 5.0 Wt.% of aluminum, 0 to 5.0Wt.% of silicon, 0 to 5.0 Wt.% of tin, 0 to 5.0 Wt.% of antimony, 0 to 10.0 Wt.% of cobalt and 0 to 10.0 Wt.% of copper, is further added to the melt; and the molten metal thus prepared is thoroughly agitated to homogenize its composition.

For the purpose of testing, a number of different alloy specimens were prepared inthe aforesaid manner. Each of the alloy melt was poured into a mold having a several shape and size for producing a sound ingot. The ingot was than shaped into sheets, each being 0.3 mm thick, by forging or rolling at a room temperature or a high temperature.

Rings with an outer diameter of 44 mm and an inner diameter of36 mm were punched out of the sheets thus prepared. The rings were then heated at 800C or higher, preferably at above l,l00C'but below the melting point, for at least lminute, preferably about hours, in vacuo or in hydrogen or other nonoxidizingatmosphere, and then gradually cooled ata suitable cooling speed depending on the alloy composition such as 100C/second to lC/hour, preferably 10C/second to 10C/hour. For certain alloy compositions, the specimens were further heated at-a temperature below their order-disorder transformation point, i.e., lower than -the order-disorder transformation point, particularly 200 to 600C for at least 1 minute but not longer than about 100 hours, and then cooled.

The permeability ofthe ring specimens thus obtained was measured by a conventional ballistic galvanometer method. The highest values of the initial permeability (;.t,,) and the maximum permeability (a of the specimens proved to be 87,300 and 379,000, respectively. It was also found that the specimens had a considerably high hardness and a large specific resistivity.

For a better understanding of the invention, reference is made to theaccompanying drawings, in which: FIGS..1A. and 1B are graphs illustrating the relation between the composition of nickel-iron-tantalummolybdenum alloys containing about 2.1 Wt.% of certain molybdenum, respectively, and their initial permeability and maximum permeability;

v FIGS. 2A and 2B are graphs illustrating the relation between the composition of nickel-iron-tantalumchromium alloys containing about 2.2 Wt.% of certain chromium, respectively, and their initial permeability and maximum permeability.

FIGS. 3A and 3B are graphs illustrating therelation between the composition of nickel-iron-tantalumtungsten alloys containing about 3.2 Wt.% of certain tungsten, respectively, and their initial permeability and maximum permeability;

FIGS. 4A and 4B are graphs illustrating the relation between the composition of nickel-iron-tan talumvanadium alloys containing about 3.0 Wt.% of certain vanadium, respectively, and their initial permeability and maximum permeability; and

FIGS. 5A and 5B are graphs illustrating the relation between the composition 'of nickel-iron-tantalumgermanium alloys containing about 3.1 Wt.% of certain germanium, respectively, and their initial permeability and maximum permeability.

Embodiments of the present invention will be explained hereinafter.

Manufacture of alloy No. 21 (consisting of 74.0 Wt.% of Ni, 9.9 Wt.% of Fe, 14.0 Wt.% of Ta and 2.1 Wt.% of Mo).

As a starting material, 99.8%-pure electrolytic nickel, 99.9%-pure electrolytic iron, 99.97c-pure tantalum and 99.97c-pure molybdenum were used. A sample was formed by melting 800 g of the starting pure metals in vacuo by using an alumina crucible disposed in a high-frequency electric induction furnace, agitating the molten metal so as to produce a homogeneous melt of the alloy, and pouring the melt into a metallic mold having a cylindrical hole of 25 mm diameter and 170 mm height. The ingot thus obtained was forged at about 1,000C into 7 mm thick sheets. The sheets were hot rolled at about 600 to 900C to a thickness of 1 mm, and then cold rolled at a room temperature to make them into thin sheets of0.3 mm thickness. Rings with an inner diameter of 36 mm and an outer diameter of 44 mm were punched out from the thin sheets.

The rings thus formed were subjected to different heat treatments as shown in Table 1. Physical proper- 5 ties of the rings after the treatments are also shown in ltbls 1 EXAMPLE 2 Table 1 Residual Initial Maximum magnetic Coercive Hysteresis Saturated Specific Heat treatment permeapermeaflux force loss magnetic flux electric Vickers bility bility density (Oe) (erg/cm l density resistance hardness #0 1 y l (uQ- H Maximum magnetic flux Magnetic density=5,000 G fie1d=900 Oe Heated at 1,150C in hydrogen for 3 17,000 115,000 3,330 0.0164 27.31 5,550 72.5 204 hours, cooled to 600C in furnace, and cooled to room temperature at 9C/second. After said treatment, reheated at 400C 33,000 215,000 in vacuo for 30 minutes. Heated at 1,150C in hydrogen for 3 38,900 174,000 3,310 00086 14.28 5,570 73.0 202 hours, cooled to 600C in furnace, and cooled to room temperature at 8,100C/hour. After said treatment, reheated at 400C 41,000 206,000 in vacuo for l hour. Heated at 1,150C in hydrogen for 3 62,000 293,000 3,280 0.0053 8.67 5,580 73.5 203 hours, cooled to 600C in furnace, and cooled to room temperature at 240C/hourv After said treatment, reheated at 400C 46,400 235,000 in vacuo for 30 minutes. Heated at 1,150C in hydrogen for 3 87,300 379,000 3,350 0.0041 6.45 5,600 73.4 202 hours, cooled to 600C in furnace, and cooled to room temperature at l00C/hour. After said treatment, reheated at 400C 52,600 264,000 in vacuo for 1 hour. Heated at 1,150C in hydrogen for 3 33,000 154,000 3,340 0.0093 16.46 5,570 73.2 202 hours, cooled to 600C in furnace, and cooled to room temperature at 10C/hourv After said treatment, reheated at 400C 14,600 103,000 3,320 0.0170 28.60 a. in vacuo for 3 hours.

Table 2 Residual Initial Maximum magnetic Coercive Hysteresis Saturated Specific Heat treatment permeapermeaflux force loss magnetic flux electric Vickers bility bility density (0e) (erglcm/ density resistance hardness #0 i cy l (HQ-cm) Hv Maximum magnetic flux Magnetic density=5,000 G fteld=900 Oe Heated at 1,150C in hydrogen for 3 16,500 137,000 3,180 0.0164 18.42 6,010 69.3 218 hours, cooled to 600C in furnace, and cooled to room temperature at 26C/second. After said treatment, reheated at 400C 34,000 183,000 in vacuo for 30 minutesv Heated at 1.150% in hydrogen for 3 42,000 235.000 6.030 69.5 216 hours. cooled to 600C in furnace. and cooled to room temperature at 800C] hour. After said treatment. reheated at 50.100 246,000 3.130 0.007 10.73 400C for 1 hour. Heated at 1.150C in hydrogen for 3 63.600 316.000 3.140 0.0061 885 6,000 69.0 218 hours. cooledtg600i infurnace, and

cooledt o ro'om temperature at 800C/ hour.

Table 2 Continued Residual Initial Maximum magnetic Coercive Hysteresis Saturated Specific Heat treatment permeapermeaflux force loss magnetic flux electric Vickers bility bility density (Oe) (erg/cm"/ density resistance hardness #1 1 cycle) (G) (#Q-cm) Hv Maximum magnetic flux Magnetic density=5,000 G field=900 Oe After said treatment, reheated at 52,000 247,000 400C in vacuo for 30 minutes. Heated at 1.150C in hydrogen for 3 51,600 256,000 3.160 0.0075 10.24 6.000 69.2 220 hours. cooled to 600C in furnace, and cooled to room temperature at 400C] hour. After said treatment, reheated at 36,500 171,000 400C in vacuo for 1 hour. Heated at 1,150C in hydrogen for 3 32,400 157.000 3.090 0.0103 12.47 6.010 68.7 218 hours. cooled to 600C in furnace, and cooled to room temperature at 100C/ hour. After said treatment, reheated at 25.300 1 16,000 3,100 0.0120 14.63 400C in vacuo for 1 hour.

1! EXAMPLE 3 EXAMPLE 4 Manufacture of alloy No. 207 (consisting of 73.3 Wt.% of Ni, 8.2 Wt.% of Fe, 15.2 Wt.% of Ta and 3.1 Wt.% of Ge).

As a starting material, nickel, iron and tantalum each having the same purity as those in Example 1 and 99.97r-pure germanium were used. A method of manufacturing the sample was in the similar manner as Ex- Manufacture of alloy No. 228 (consisting of 74.0 Wt.% of Ni, 8.9 Wt.% of Fe, 15.l Wt.% of Ta and 2.0 Wt.% of Ti).

As a starting material, nickel, iron, and tantalum each having the same purity as those in Example 1 and 99.8%-pure titanium were used. A method of manufacturing the sample was in the similar manner as Example in vacuo for 1 hour.

ample 1. Different heat treatments were applied to the 1. Different heat treatments were applied to the samsamples and the physical properties thereof were obples and the physical properties thereof were obtained tamed as shown 111 Table 3. as shown in Table 4.

Table 3 Residual Initial Maximum magnetic Coercive Hysteresis Saturated Specific Heat treatment permeapeermeaflux force loss magnetic flux electric Vickers bility bility density (0e) (erg/cm! density resistance hardness a, p.,,, G) cycle) (G) (;1.Q-cm) Hv Maximum magnetic flux Magnetic density=5,000 G field=900 Oe Heated at l,lC in hydrogen for 3 17,800 103,000 3,070 0.0162 25.30 5,710 72.5 265 hours, cooled to 600C in furnace, and

cooled to room temperature at 9C/second.

After said treatment, reheated at 400C 28,000 154,000

in vacuo for 30 minutes. 7

Heated at 1,150C in hydrogen for 3 36,400 175,000 3,090 0.0125 19.69 5,700 72.7 263 hours, cooled to 600C in furnace, and

cooled to room temperature at 8,100C/hour.

After said treatment, reheated at 400C 47,200 203,000 3,150 0.0098 17.62

in vacuo for 1 hour.

Heated at 1,150C in hydrogen for 3 53,600 224,000 3,100 0.0086 15.48 5,710 72.4 265 hours, cooled to 600C in furnace, and

cooled to room temperature at 800C/hour.

After said treatment, reheated at 400C 58,800 232,000

in vacuo for 30 minutes.

Heated at 1,150C in hydrogen for 3 72,500 287,000 3,130 0.0074 12.83 5,730 72.2 265 hours, cooled to 600C in furnace, and

cooled to room temperataure at 240C/hour.

After said treatment, reheated at 400C 53,000 241,000

in vacuo for 1 hour.

Heated at 1,150C in hydrogen for 3 46,600 216,000 3,120 0.0094 16.70 5,710 72.6 267 hours, cooled to 600C in furnace, and

cooled to room temperature at C/hour.

After said trcatmcnt, reheated at 400C 23,700 157,500

Table 4 Residual Maximum magnetic Coercive flux density (G) Initial Hysteresls Saturated permeapermeaforce loss magnetic flux electric Vickers biltty bllity (Oe) (erglcm l density resistance hardness #0 I cycle) (G) (uQ-cml H\ Maximum magnetic flux Magnetic density=5,000 G field=900 0e Heat treatment Heated at 1,150C in hydrogen for 3 hours, cooled to 600C in furnace, and cooled to room tem 26C/second.

perature at After said treatment, reheated at 400C in vacuo for minutes.

Heated at 1,150C in hydrogen for 3 22,000 254,000 hours, cooled to 600C in furnace, and

cooled to room temperature at 8,l0OC/hour.

After said treatment. reheated at 400C 28,300 262,000 in vacuo for 1 hour.

7 Heated at 1.150C in hydrogen for 3 hours. cooled to 600C in furnace. and cooled to room temperature at 240C] hour.

After said treatment. reheated at 400C 31.600 246,000 in vacuo for 30 minutes.

m n a inm me m fr dmw h m na W d w m mm e 00 hour.

After said treatment, reheated at 400C 20.400 136.000 in vacuo for 1 hour.

Heated at l. l C in hydrogen for 3 hours. cooled to 600C in furnace. and cooled to room temperature at 10C/ hour.

Al'ter said treatment. reheated at 400C 13.500 104,000 in vacuo for 1 hour.

ln the above Ex imples, the metals V and Nb having a purity of 99.8%

Further, in the above Examples, each alloy was heated at 1,150C for 3 hours, cooled to 600C in a furwere used, but conventional ferrovanadium and ferro-niobium available on the market can be used. In such a case f nace, and further treated by various heat treatments. This heating temperature can be more than 800C an alloy slightly becomes ragile, so that a deoxidizer and desu lfurizer, e.g., manpreferably above 1,100

C and below the melting point and the heating time is not limited.

Further, the characteristics of the t as shown in Table .-Iable ypical alloys are 5 an QBV 5425 6200 1850 7502 03 6432 kduh 5602 5727 5727 8322 12 5757 m 1122 1122 1122 1222 22 1122 Vb 8 CCC 1.1 n) frflm 646 4813 $17 063 04 624 10 CC!- 830 8070 251 056 95 935 9:2 677 677B 660 a. 67 56 n.1 3u 1 1 sca T M 8 d1 O 827 0 t t 0 0000 000 000 00 000 80 1) C9 7353 491 826 0B 152 T150 1- 5321 .070 .097 00 .070 Uta td ill II! I! II I BM. M. 6665 765 555 66 765 5 0 81 M 3 M S \J 1 ,8 5 a 1 G .GSmC Z553 2104 5730 4352 6074 ISCV 0 4745 3637 5416 4601 84 5152 eO/C 0 618 M0 9966 8295 0700 7438 03 6307 W H 2 1 11 3 4113 3212 1 4113 H y 6 Ct V 1 1 0510 6492 6362 5245 16 3296 .18) t5 9641 3750 0164 3407 60 8079 CCe on 1001 1002 2102 2101 01 2101 rrO no 0000 0000 0000 0000 00 0000 o f m 0000 0000 0000 0000 00 0000 1C y E 111111 8 1 t u 0000 0000 0000 0000 00 0000 utxi m 7254 6267 2754 7186 49 3625 deus) 1 0138 2098 6417 1019 10 5436 in n 1...... ..-.n| I... ran: Ina %Mf .m m 3332 3322 3332 3332 33 3332 m .7 0000 0000 0000 0000 00 0000 mat 0000 0000 0000 0000 00 0000 mei 0004 0000 2007 2035 05 0000 m 11); v!!! tun! 19: t: 1!!! uminr 4590 4176 0849 5414 62 3640 c 0278 3539 5874 6790 10 7365 M 1331 123 12 121 31 12 Y. 0000 0000 0000 0000 00 0000 886 0000 0000 0000 0000 00 0000 iei 0237 2110 0354 5095 62 4976 t10 var. nest Ir: lira r as: imiu. 3576 B836 4628 0603 34 7059 neb 1783 1351 147 1241 63 24 D. t 0 0 0 0 nae u a 5 3 1 1r?- 0 tan b ap I... em hB C 0 0 0 0 et a 2 0 0 2 R 4 4 4 4 \1 g 8 CT Educ-1B n u .1 6 1 00 0000 0000 0500 0000 0000 1et0ttt5h 4400 4150 4 04 0004 0044 opf0flfla1u 2211 2 1 2 12 1142 8422 S 6 v m h 16 f 0210 5220 5020 5302 5102 -a.- -..w--.v.-. m...- M6421 C4321 B631 6531 0642 n 1203 0023 0305 5020 2035 O 8 .1. ...n 1 T 5848 5050 4050 3706 5050 t 112 112 11 112 .1 1 S 6695 0832 S730 0248 1921 1k 6 D. F 2197 4087 2998 4119 9877 m 11 11 1 111 o C 3002 5035 0055 0540 2052 N 6643 6641 5420 6653 7530 7777 7777 7777 7777 7777 y 0 5219 8520 1863 1830 0752 10 3456 7789 0012 6678 MN 1111 1111 M Table 5:Continued span Ros ual H 1 s d from Rehoating magnetic coercivl a nut. Composition 600C tomperai flux force "v.71: flux sped; V1.03"! allay u) an" tun emea purnea dens (org/cm density electric h as No. bility bility Y cycle) a) ruhtanco heating hour u u (0) (when [iv 1 {g Maximum u atlc flux Ma otic H1 Fe Ta [ea/hour) 6n51ty'5,000 G f 61(1'900 0e v 190 77.4 11.4 5.2 6?0 240 19,200 124,000 3,460 0.0135 21.46 163 197 76.0 8.5 10.0 5.5 240 48,300 216,600 3,070 0.0092 16.31 5,960 68.4 220 207 73.3 8.2 15.2 3.1 240 72,500 287,000 3,130 0.0074 12.83 5,730 72.2 265 214 71.0 7.5 20.3 1.2 100 16,400 73,500 2,530 0.0120 36.05 5,000 102.3 273 As understood from the Examples, figures and Table 5, in the Ni-Fe-Ta alloy added with the total amount of more than 0.01% and less than 10.0% selected from the group consisting of Mo, Cr, W, V, Nb, Mn, Ge, Ti, Zr, A1, Si, Sn, Sb, Co and Cu according to the present invention, the highest values of the initial permeability and the maximum permeability are very large, for instance, the alloy (No. 21 in Table 5) consisting of 74.0 Wt.% of nickel, 9.9 Wt.% of iron, 14.0 Wt.% of tantalum and 2.1 Wt.% of molybdenum heated at 1,150C for 3 hours, cooled to 600C in a furnace, maintained at the same temperature for 10 minutes, and further cooled to a room temperature at 100C/hour, which initial permeability and the maximum permeability are 87,300 and 379,000, respectively, and its hardness l-lv is 202. These characteristics of the Ni-Fe-Ta alloys are remarkable as compared with the alloy consisting of 73.0 Wt.% ofNi, 12.0 Wt.% of Fe and 15.0 Wt.7c of Ta and the alloy consisting of 75.5 Wt.% of Ni, 13.5 Wt.% of Fe and l [.0 Wt.% of Ta, which are heated at l,250C for 3 hours, cooled to 600C in a furnace, maintained at the same temperature for 10 minutes, and further cooled to a room temperature at 400C/hour and 240C/hour. The initial permeability (the former alloy) is 34,800 and the maximum permeability (the latter alloy) is 256,000 and the hardness Hv 2l0 and I92, respectively.

As described in the foregoing, with the method according to the present invention, the heat treatment may be completed only by a primary treatment, which consists of heating a ternary alloy with a composition falling in the specific range of the invention, in a nonoxidizing atmosphere or in vacuo at 800C or higher,

LII

LII

perature at a cooling speed of C/second to 1C/hour, preferably lOC/second to lOC/hour, depending on the alloy composition.

According to the present invention, it is also preferable to apply a secondary heat treatment to the alloy treated by the aforesaid primary heat treatment, which secondary heat treatment comprises steps of heating the alloy in a non-oxidizing atmosphere or in vacuo at a temperature below the order-disorder transformation point of the alloy, i.e., at about 600C, for at least 1 minute, but not longer than 100 hours, and then gradually cooling.

Thesecondary heat treatment is carried out after cooling the alloy to a room temperature at a suitable speed depending on the alloy composition from about 600C at the primary heat treatment, but it can be carried out after cooling the alloy to a preferable temperature of less than the order-disorder transformation point but more than the room temperature at a suitable speed from about 600C at the primary heat treatment.

Conventional materials for magnetic recording and reproducing heads have a shortcoming in that the passage of magnetic tape in contact with such heads tends to abrade the heads, which head abrasion may cause deterioration of the quality of the signals, e.g., sound quality, recorded or reproduced by the head.

Accordingly, the alloy for magnetic heads should preferably have a high hardness and a high abrasion resistivity. Conventional nickel-iron alloys for magnetic heads have a Vickers hardness Hv in the order of about 130, which is not high enough for ensuring a high abrasion resistivity. On the other hand, the Vickers hardness of the alloy according to the present invention increases with the addition ofthe total amount of 0.01 to 10.0% selected from the group consisting of Mo, Cr, W, V, Nb, Mn, Ge, Ti, Zr, Al, Si, Sn, Sb, Co and Cu, as shown in the Examples and Table 5, and a Vickers hardness Hv as high as 151 to 396 can be obtained. Thus, the abrasion resistivity of magnetic material for recording and reproducing heads is noticeably improved by the present invention. The most important characteristics of the alloy according to the present invention is the highest hardness.

The electric resistivity of magnetic recording and reproducing heads should preferably be high, for suppressing the eddy current loss therein. The specific resistivity of conventional binary alloy consisting of 79 Wt. 7( of nickel and 21 Wt.% of iron is in the order of 16 nQ-cm. On the other hand, with the alloys according to the present invention, the specific resistivity is as high as 57 to 1 l2 nQ em as can be seen from the Examples and Table 5. This high specific resistivity is also one of the characteristics of the alloy according to the present invention.

Magnetic heads are usually made by laminating thin sheets of the alloy material, which sheets are in turn formed by rolling and cutting into suitable shape by punching. Thus, the alloy for magnetic heads should have a high workability. The alloys according to the present invention are as easily workable as conventional nickel-iron binary alloy; namely, the alloy of the invention can easily be forged, rolled, drawn, swaged, or punched.

The high hardness of the alloy according to the present invention makes the alloy particularly suitable for magnetic recording and reproducing heads, as pointed out in the foregoing. Furthermore, the outstandingly high permeability and the high specific resistivity of the alloy of the invention are also attractive in conventional electric and magnetic devices of various other types.

According to the present invention, the contents of nickel, iron and tantalum are restricted to 60.2 to 85.0 Wtf/r, 6.0 to 30.0 Wt.% and 3.1 to 23.0 Wt.%, respectively, and further the contents of the subingredients added thereto are restricted to 0.01 to 10.0 Wt.% selected from the group consisting of to 7.0 Wt.% of molybdenum, 0 to 5.0 Wt.% of chromium, 0 to 10.0 Wt.7( of tungsten, 0 to 7.0 Wt.% of vanadium, 0 to 3.1 Wt.% of niobium, 0 to 10.0 Wt.% of manganese, 0 to 7.0 Wt.% of germanium, 0 to 5.0 Wt.% of titanium, 0 to 5.0 Wt.71 of zirconium, 0 to 5.0 Wt.% of aluminum, 0 to 5.0 Wt.7( of silicon, 0 to 5.0 Wt.% of tin, 0 to 5.0 Wtf/z of antimony, 0 to l0.0 Wt.% of cobalt, and 0 to 10.0 Wt./1 of copper. The reason why the content of alloys according to the present invention is restricted is that the alloy composition in the aforesaid range shows a high permeability and a high hardness suitable for magnetic heads, but the alloy composition outside the aforesaid range shows the decrease of permeability and hardness to use the alloy for magnetic heads.

The suitable contents of the ingredients in the alloy according to the present invention will now be described in further detail.

1. Nickel 60.2 to 85.0 Wt.%.

With the nickel content of 60.2 to 85.0 Wt.7(, excellent magnetic properties can be achieved, i.e., an initial permeability n of 87,300 and a maximum permeability n,,, of 379,000. With the nickel content less than 60.2 Wt.%, the initial permeability n and the maximum permeability n,,, are reduced to levels below 3,000 and 5,000, respectively. On the other hand, with the nickel content in excess of 85.0 Wt.%, the initial permeability n becomes less than 3,000, despite that a comparatively high maximum permeability n,,, can be achieved. Thus, the nickel content is restricted to 60.2 to 85.0 Wt.%. Further the preferable range of the nickel content is 70.0 to 80.0 Wt.%.

2. Iron 6.0 to 30.0 Wt.7(..

With the iron content of 6.0 to 30.0 Wt.7(, excellent magnetic properties can be obtained. On the other hand, with the iron content of less than 6.0 Wtf/z, the initial permeability n and the maximum permeability n are always below 3,000 and 5,000, respectively. Further, with the iron content in excess of 30.0 Wtf/e, the initial permeability n,, and the maximum permeability n are also reduced to levels below 3,000 and 5,000, respectively. Thus, the iron content is restricted to 6.0 to 30.0 Wt.7(. Further, the preferable range of the iron content is 8.0 to 20.0 Wt.%.

3. Tantalum 3.] to 23.0 Wtf/z.

With the tantalum content in the aforesaid range, excellent magnetic properties and high hardness can be obtained. On the other hand, with the tantalum content ofless than 3.l Wt.%, it becomes difficult to ensure the Vickers hardness Hv to be not smaller than l50. When the tantalum content increases in excess of 23.0 Wt.7z, the initial permeability n and the maximum permeability n,,, becomes smaller than 3,000 and 5,000, respec tively. The excessively high tantalum content also re sults in the deterioration ofthe workability of the alloy, especially its forgeability and rollability. Thus, the tantalum content is restricted to 3.1 to 23.0 Wt.%. Further, the preferable range ofthe tantalum content is 6.0 to 17.0-Wtf/r.

4. Molybdenum 0 to 7.0 Wt.% (exclusive of 0 /1).

With the molybdenum content of0 to 7.0 WtT/z, excellent magnetic properties can be obtained, i.e., the initial permeability n of 87,300 and the maximum permeability n,,, of 379,000. On the other hand, with the molybdenum content in excess of Wt.%, the forgeability and the rollability of the alloy are deteriorated. Thus, the molybdenum content is restricted to 0 to 7.0 Wt.7(, preferably less than 4.0 Wt.

5. Chromium 0 to 50 Wt.% (exclusive of 0%).

With the chromium content of0 to 5.0 Wt./z, the initial permeability n,, of53,l00 can be achieved, but with the chromium content of more than 5.0 Wtf/r, the initial permeability n and the maximum permeability n,,, become less than 3,000 and 5,000, respectively. Thus, the chromium content is restricted to 0 to 5.0 Wt.'/r.. Further, the preferable range of the chromium content is less than 3.0 Wt./.

6. Tungsten =0 to 10.0 Wtf/r (exclusive of 0/( With the tungsten content of0 to l0.0 Wt./r, the initial permeability n,, shows the highest value of 72,500,

but with the tungsten content in excess of 10.0 Wt.%, the initial permeability ,u,, and the maximum permeability ,u.,,, are reduced to less than 3,000 and 5,000, respectively. The excessively high tungsten content also results in the deterioration of the forgeability and the rollability of the alloy. Thus, the tungsten content is restricted to to 10.0 Wt.%. Further, the preferable range of the tungsten content is less than 5.0 Wt.%.

7. Vanadium 0 to 7.0 Wt.% (exclusive of 0%).

With the vanadium content of 0 to 7.0 Wt.%, excel-- With the niobium content of0 to 3.1 Wt.%, excellent magnetic properties can be obtained and forgeability and rollability can be improved, but with the niobium content in excess of3.l Wt.%. its effect is reduced. Accordingly, the niobium content is restricted to 0 to 3.1 Wt.%.

9. Manganese 0 to 10.0 Wt.% (exclusive of 0%).

With the manganese content of0 to 10.0 Wt.%, the initial permeability ,u, is 45,700 and excellent magnetic properties can be obtained. On the other hand, with the manganese content of more than 10.0 Wt.%, the initial permeability ,u, and the maximum permeability, M," become less than 3,000 and less than 5,000, respectively. Thus, the manganese content is restricted to 0 to 10.0 Wt.%. Further, the preferable range of the manganese content is less than 5.0 Wt.%.

10. Germanium 0 to 7.0 Wt.% (exclusive of 0%).

With the germanium content of0 to 7.0 Wt.%, excellent magnetic properties can be obtained showing the highest initial permeability ,u of 72,500. On the other hand, with the germanium content in excess of 7.0 Wt.%, the initial permeability ,u.,, and the maximum permeability become less than 3,000 and less than 5,000, respectively. Thus, the germanium content is restricted to 0 to 7.0 Wt.%. Further, the preferable range of the germanium content is less than 5.0 Wt.%.

ll. Titanium 0 to 5.0 Wt.% (exclusive of 0%).

With the titanium content of0 to 5.0 Wt.%, excellent magnetic properties and high hardness can be obtained. On the other hand, with the titanium content in excess of 5.0 Wt.%, the initial permeability ,u. and the maximum permeability pt become less than 3,000 and 5,000, respectively. The excessively high titanium content also results in the deterioration of the forgeability and the rollability of the alloy. Thus, the titanium content is restricted to 0 to 5.0 Wt.%. It is more preferable to restrict it to less than 3.0 Wt.%.

l2. Zirconium 0 to 5.0 Wt.% (exclusive of 0%).

With the zirconium content of 0 to 5.0 Wt.%, excellent magnetic properties and high hardness can be obtained. On the other hand, with the zirconium content in excess of 5.0 Wt.%, the initial permeability u and the maximum permeability ,u become less than 3,000 and 5,000, respectively. Further, the forgeability and the rollability of the alloy also are deteriorated. Thus, the zirconium content is restricted to 0 to 5.0 Wt.%. The preferable range of the zirconium content is less than 3.0 Wt.%

13. Aluminum 0 to 5.0 Wt.% (exclusive of 0%).

With the aluminum content of 0 to 5.0 Wt.%, excellent magnetic properties and high hardness can be obtained. On the other hand, with the aluminum content in excess of 5.0 Wt.%, the initial permeability ,u,, and the maximum permeability ,u.,,, become less than 3,000 and 5,000, respectively. The excessively high aluminum content also results in the deterioration of the forgeability and the rollability of the alloy. Thus, the aluminum content is restricted to 0 to 5.0 Wt.%. The preferable range of the aluminum content is less than 30 Wt.%.

14. Silicon 0 to 5.0 Wt.% (exclusive of 0% With the silicon content of 0 to 5.0 Wt.%, excellent magnetic properties and high hardness can be obtained. On the other hand, the silicon content in excess of 5.0 Wt.%, the initial permeability and the maximum permeability M become less than 3,000 and 5,000, respectively, and further the forgeability and the rollability of the alloy are deteriorated. Thus, the silicon content is restricted to 0 to 5.0 Wt.%. The prefera ble range of the silicon content is less than 3.0 Wt.%.

15. Tin 0 to 5.0 Wt.% (exclusive of 0%).

With the tin content of0 to 5.0 Wt.%, excellent magnetic properties and high hardness can be obtained. On the other hand, with the tin content in excess of Wt.%, the forgeability and the rollability of the alloy are deteriorated. Thus, the tin content is restricted to 0 to 5.0 Wt.%. The preferable range of the tin content is less than 3.0 Wt.%.

16. Antimony 0 to 5.0 Wt.% (exclusive of 0%).

With the antimony content of 0 to 5.0 Wt.%, excellent magnetic properties and high hardness can be obtained. On the other hand, with the antimony content in excess of 5.0 Wt.%, the forgeability and the rollability are deteriorated. Thus, the antimony content is restricted to 0 to 5.0 Wt.%. The preferable range of the antimony content is less than 3.0 Wt.%.

17. Cobalt 0 to 10.0 Wt.% (exclusive of 0%).

With the cobalt content ofO to 10.0 Wt.%, excellent magnetic properties can be obtained. On the other hand, with the cobalt content in excess of 10.0 Wt.%, the initial permeability ,u,, and the maximum permeability t, become less than 3,000 and 5.000, respectively. Thus, the cobalt content is restricted to 0 to 10.0 Wt.%. The preferable range of the cobalt content is less than 5.0 Wt.%.

l8. Copper 0 to 10.0 Wt.% (exclusive of 0%).

With the copper content of0 to l0.0 Wt.%, excellent magnetic properties can be obtained. On the other hand, with the copper content in excess of l0.0 Wt.%, the initial permeability ,u.,, and the maximum permeability p.,,, become less than 3,000 and 5,000, respectively. Thus, the copper content is restricted to 0 to 10.0 Wt.%. The preferable range of the copper content is less than 5.0 Wt.%.

Further, a total amount of the subingredients (4) to (18) is 0.01 to 10.0 Wt.%, because the alloy composition outside the aforesaid range results in the deterioration of the magnetic properties, the forgeability and the rollability of the alloy. Further, the content of subingredient of less than 0.01 Wt.% shows no addition effect.

In short, the alloy according to the invention consists of 60.2 to 85.0 Wt.%, preferably 70.0 to 80.0 Wt.% of nickel, 6.0 to 30.0 Wt.%, preferably 8.0 to 20.0 Wt.% of iron, and 3.] to 23.0 Wt.%, preferably 6.0 to 17.0

Wt./( of tantalum, and further consists of at least one element, which total amount is 0.01 to 10.0 Wt.%, selected from the group consisting of to 7.0 Wt.%, preferably 0 to 4.0 Wt.% of molybdenum, 0 to 5.0 Wt.%, preferably 0 to 3.0 Wt.% of chromium, 0 to 10.0 Wt.%, preferably 0 to 5.0 Wt.% of tungsten, 0 to 7.0 Wt.%, preferably 0 to 4.0 Wt.% of vanadium (or conventional ferro-vanadium available on the market instead of metallic vanadium), 0 to 3.1 Wt.% of niobium (or conventional ferro-niobium available on the market instead of metallic niobium), 0 to l0.0 Wt.%, preferably 0 to 5.0 Wt.% of manganese, 0 to 7.0 Wt.%, preferably 0 to 5.0 Wt.% of germanium, 0 to 5.0 Wt.%, preferably 0 to 3.0 Wt.% of titanium, 0 to 5.0 Wt.%, preferably 0 to 3.0 Wt.% of zirconium, 0 to 5.0 Wt.%, preferably 0 to 3.0 Wt.% of aluminum, 0 to 5.0 Wt.%, preferably 0 to 3.0 Wt.% of silicon, 0 to 5.0 Wt.%, preferably 0 to 3.0 Wt.% of tin, 0 to 5.0 Wt.%, preferably 0 to 3.0 Wt.% of antimony, 0 to 10.0 Wt.%, preferably 0 to 5.0 Wt.% of cobalt, and 0 to 10.0 Wt.%, preferably 0 to 5.0 Wt.% of copper (each being exclusive of 0%) as the subingredient, and an inevitable amount of impurities. An ingot of the alloy of the invention may be made by pouring a melt of the alloy into a suitable mold. The ingot may be shaped into a desired form by working it at a room temperature or at an elevated temperature, for instance by forging. rolling, drawing, swaging, or

' the like. After the shaping, the alloy is heat treated by heating it at a high temperature such as a temperature of more than 800C, preferably higher than l,l00C but lower than the melting point, in hydrogen or a nonoxidizing atmosphere or in vacuo for at least 1 minute but not longer than 100 hours, and then cooling it to a room temperature at a cooling speed of from l00C/second to lC/hour, preferably l0C/second to l0C/hour, depending on the alloy composition. For certain alloy compositions, the alloy may be reheated to a temperature below about 600C, i.e., less than the order-disorder transformation point, for at least 1 minute but not longer than about 100 hours.

With such heat treatment, high permeability including an initial permeability of 87,300 and a maximum permeability of 379,000 can be obtained. In addition to the high permeability, the alloy according to the invention has a comparatively large specific resistivity and high hardness suitable for magnetic recording and reproducing heads; namely easy forgeability, rollability, drawability and swageability.

What is claimed is:

l. A method of manufacturing a high permeability and high hardness alloy for use for magnetic recording and reproducing heads comprising, melting an alloy consisting of 60.2 to 85.0 Wt. /1 of nickel, 6.0 to 30.0 Wt. "/1 of iron and 3.1 to 23.0 Wt. of tantalum as the main ingredient, and further consisting of the total amount of 0.01 to 10.0 Wt. of at least one element selected from the group consisting of 0 to 7 Wt. of molybdenum, 0 to 5.0 Wt. of chromium, 0 to I00 Wt. 7( of tungsten, 0 to 7.0 Wt. of vanadium, 0 to 3.1

Wt. of niobium, 0 to 10.0 Wt. of manganese, 0 to 7.0 Wt. 7c of germanium, 0 to 5.0 Wt. /z of titanium, 0 to 5.0 Wt. of zirconium, 0 to 5.0 Wt. 7r of aluminum, 0 to 5.0 Wt. of silicon, 0 to 5.0 Wt. 71 of tin, 0 to 5.0 Wt. of antimony, 0 to I00 Wt. 71 of cobalt, and 0 to 10.0 Wt. '/r of copper as the subingredient, and an inevitable amount of impurities so as to form an alloy having a homogenized solid solution structure, heating at a temperature of more than 800C, in a nonoxidizing atmosphere or in vacuo, for at least more than 1 minute but not longer than hours depending upon the composition, and cooling from a temperature of more than the order-disorder transformation point of about 600C to a room temperature at a suitable speed depending upon the composition so as to provide the degree of order of 0.1 to 0.6, the Vickers hardness of more than 150, initial permeability of more than 3,000 and maximum permeability of more than 5,000.

2. A method of manufacturing a Ni-Fe-Ta alloy having high permeability and high hardness for use for magnetic recording and reproducing heads comprising, melting an alloy consisting of 60.2 to 85.0 Wt. 7r of nickel, 6.0 to 30.0 Wt. 7c of iron and 3.1 to 23.0 Wt. of tantalum as the main ingredient, and further consisting of the total amount of 0.01 to 10.0 Wt. (76 of at least one element selected from the group consisting of 0 to 7.0 Wt. 7e of molybdenum, 0 to 5.0 Wt. /1 of chromium, 0 to 10.0 Wt. of tungsten, 0 to 70 Wt. /z of vanadium, 0 to 3.1 Wt. of niobium, 0 to 10.0 Wt. 7r of manganese, 0 to 7.0 Wt. of germanium, 0 to 50 Wt. of titanium, 0 to 5.0 Wt. of zirconium, 0 to 5.0 Wt. 7c of aluminum, 0 to 5.0 Wt. of silicon, 0 to 5.0 Wt. of tin, 0 to 5.0 Wt. 7( of antimony, 0 to 10.0 Wt. of cobalt, and 0 to 10.0 Wt. 71 of copper, and an inevitable amount of impurities, heating it at a temperature of more than 800C, but lower than the melting point, in a non-oxidizing atmosphere or in vacuo, for at least more than 1 minute but not longer than 100 hours, cooling it to a room temperature from a temperature of more than the order-disorder transformation point of about 600C at a suitable cooling speed of from l00C/second to lC/hour depending upon the alloy composition, and further heating it at a temperature of less than the order-disorder transformation point of about 600C, in a non-oxidizing atmosphere or in vacuo, for at least more than 1 minute but not longer than 100 hours depending upon the alloy composition, and cooling it to a room temperature at a suitable cooling speed from 100C/second to lC/hour so as to pro vide the degree of order of0.l to 0.6, the Vickers hardness or more than 150, initial permeability of more than 3,000 and maximum permeability of more than 5,000.

3. The process of claim 1 wherein said heating at a temperature of more than 800C is carried out at a temperature more than l,l00C.

4. The process of claim 2 wherein said heating at a temperature of more than 800C is carried out at a temperature of more than 1,l00C. 

1. A METHOD OF MANUFACTURING A HIGH PERMEABILITY AND HIGH HARDNESS ALLOY FOR USE FOR MAGNETIC RECORDING AND REPRODUCING HEADS COMPRISING, MELTING AN ALLOY CONSISTING OF 60.2 TO 85.0 WT. % OF NICKEL, 6.0 TO 30.0 WT. % IRON AND 3.1 TO 23.0 WT. % OF TANTALUM AS THE MAIN INGREDIENT, AND FURTHER CONSISTING OF THE TOTAL AMOUNT OF 0.01 TO I0.0 WT. % OF AT LEAST ONE ELEMENT SELECTED FROM THE GROUP CONSISTING OF 0 TO 7 WT. % OF MOLYBDENUM, 0 TO 5.0 WT. % OF CHROMIUM, 0 TO 10.0 WT. % OF TUNGSTEN, 0 TO 7.0 WT. % OF VANADIUM, 0 TO 3.1 WT. % OF NIOBIUM, 0 TO 10.0 WT. % OF MANGANESE, 0 TO 7.0 WT. % OF GERMANIUM, 0 TO 5.0 WT. % OF TITANIUM, 0 TO 5.0 WT. % OF ZIRCONIUM, 0 TO 5.0 WT. % OF ALUMINUM, 0 TO 5.0 WT. % OF SILICON, 0 TO 5.0 WT. % OF TIN, 0 TO 5.0 WT. % OF ANTIMONY, 0 TO 10.0 WT. % OF COBALT, AND 0 TO 10.0 WT. % OF COPPER AS THE SUBINGREDIENT, AND AN INEVITABLE AMOUNT OF IMPURITIES SO AS TO FORM AN ALLOY HAVING A HOMOGENIZED SOLID SOLUTION STRUCTURE, HEATING AT A TEMPERATURE OF MORE THAN 800*C, IN A NONOXIDIZING ATMOSPHERE OR IN VACUO, FOR AT LEAST MORE THAN 1 MINUTE BUT NOT LONGER THAN 100 HOURS DEPENDING UPON THE COMPOSITION,AND COOLING FROM A TEMPERATURE OF MORE THAN THE ORDER-DISORDER TRANSFORMATION POINT OF ABOUT 600*C TO A ROOM TEMPERATURE AT A SUITABLE SPEED DEPENDING UPON THE COMPOSITION SO AS TO PROVIDE THE DEFREE OF ORDER OF 0.1 TO 0.6, THE VICKERS HARDNESS OF MORE THAN 150, INITIAL PERMEABILITY OF MORE THAN 3,000 AND MAXIMUM PERMEABILITY OF MORE THAN 5,000.
 2. A method of manufacturing a Ni-Fe-Ta alloy having high permeability and high hardness for use for magnetic recording and reproducing heads comprising, melting an alloy consisting of 60.2 to 85.0 Wt. % of nickel, 6.0 to 30.0 Wt. % of iron and 3.1 to 23.0 Wt. % of tantalum as the main ingredient, and further consisting of the total amount of 0.01 to 10.0 Wt. % of at least one element selected from the group consisting of 0 to 7.0 Wt. % of molybdenum, 0 to 5.0 Wt. % of chromium, 0 to 10.0 Wt. % of tungsten, 0 to 7.0 Wt. % of vanadium, 0 to 3.1 Wt. % of niobium, 0 to 10.0 Wt. % of manganese, 0 to 7.0 Wt. % of germanium, 0 to 5.0 Wt. % of titanium, 0 to 5.0 Wt. % of zirconium, 0 to 5.0 Wt. % of aluminum, 0 to 5.0 Wt. % of silicon, 0 to 5.0 Wt. % of tin, 0 to 5.0 Wt. % of antimony, 0 to 10.0 Wt. % of cobalt, and 0 to 10.0 Wt. % of copper, and an inevitable amount of impurities, heating it at a temperature of more than 800*C, but lower than the melting point, in a non-oxidizing atmosphere or in vacuo, for at least more than 1 minute but not longer than 100 hours, cooling it to a room temperature from a temperature of more than the order-disorder transformation point of about 600*C at a suitable cooling speed of from 100*C/second to 1*C/hour depending upon the alloy composition, and further heating it at a temperature of less than the order-disorder transformation point of about 600*C, in a non-oxidizing atmosphere or in vacuo, for at least more than 1 minute but not longer than 100 hours depending upon the alloy composition, and cooling it to a room temperature at a suitable cooling speed from 100*C/second to 1*C/hour so as to provide the degree of order of 0.1 to 0.6, the Vickers hardness or more than 150, initial permeability of more than 3, 000 and maximum permeability of more than 5,000.
 3. The process of claim 1 wherein said heating at a temperature of more than 800*C is carried out at a temperature more than 1, 100*C.
 4. The process of claim 2 wherein said heating at a temperature of more than 800*C is carried out at a temperature of more than 1,100*C. 